Mixing liquids



E. SCHMIDT MIXING LIQUID July 2, 1940.

Filed Sept. 16. 1939 4 Sheets-Sheet 1 IIiI/l,"

y 2, 1940- E. SCHMIDT HIKING LIQUID Filed s t; is, 1939 4 Sheets-Sheet 2 July 2, 1940. $HM|DT 2,206,266

HIKING LIQUID Filed Sept. 16, 1939 4 Sheet-Sheet 5 Patented July 2, 1940 UNITED STATES PATENT "OFFICE MIXING LIQUIDS Edward Schmidt, Methuen, Mass, assignor to Lawrence Pump' and Engine 00., Lawrence,

Mass, acorporation of Massachusetts it Application September 16, 1939, Serial No. 295,190 8 Claims. (Cl. 259-96) This invention relates toan improvement in a mixing device and more particularly in adevice of the type employed in the treatment of heavy non-diffusible liquids or of liquidswhich are to be emulsified such as tar, asphalt, paint, emul sions and the like. i

The treatment of these liquidsby a device em- 15 to differentiate between such treatments it is customary in the industry to apply the term mixing to the first treatment andthe term agitating to the second. For the purpose of describing this invention, however, the term 20 mixing is used throughout the specification to include both treatments and not in its limited sense.

The primary object of this invention is to protion, such device acting to withdraw the liquid from the bottom of a container and return such withdrawn liquids to the main body thereof at two or more levels, the withdrawn liquid being returned to the container under such pressure that it displaces the liquid therein at such levels.

Further objects of the invention reside in the.

l structure of the device and the provision of means i for breaking up the very. fine particles of the liquid, for withdrawing the liquid at the bottom of the container, for preventing the formation of an inverted vortex which interferes with the normal operation of the device, for returning graduated quantities of the withdrawn liquid to thecontainers at various levels, and for preventing the escape of liquidsfrom the container during the agitation thereof.

These and other objects will appear from a consideration of the following description of cer- 55 Ul -g,@5.-,iS a bottom plan. view of the impeller;

vice with parts shown in section; and

vide a device by which such liquids are mixed to; bring them into a uniform homogeneous condi- K Figs. 6 and 7 are cross-sectional views taken along the lines 66 and 'l--l in Fig. 1;

Figs. 8 and 9 are sectional views illustrating various ways of supporting the upper end of the mixer shaft;

Fig. 10 is. a sectional view similar to Fig. 1, with parts broken away, illustrating another embodiment of the invention;

Fig. 11 is a View in elevation of another embodiment of this invention; d 10 Fig. 12 (is an enlarged longitudinal section thereof; l

. Fig. 13 is a plan view of a portion of the de- Fig. 14 is a bottom plan view of one element 15 l The mixer shown in Figs. 1 to? inclusive comprises a shaft 2| carrying an impeller 22 at Q the bottom end and driven by a motor 23 acting upon the upper end of the shaft and suitably con- 20 nected thereto The impeller 22 is received in a base 24 and the shaft 2| is surrounded by a tubular casing 25. The motor 23 rests upon the top of the casing 25 and the base 24is removably attached to the bottom of the casing. The shaft is suspended from the motor shaft 26 and supported for rotation adjacent its lower end in a bearing 21 carried by a cross-rib 2B integral with the casing 25. l

Thebase 24 is provided with a central pocket 3D surroundedby an annular wall 3|. At the under side of the base are provided legs 33 on which the mixer is supported.

Through the wall 3i. extend ports 34 which lead from the pocket 38 to the outer face of the base. 5 The ports 34 are substantially tangential to the 1 pocket .30 and diverge outwardly as shown in i Fig. 2. In the base 2 5 are provided chambers 35 connected to the pocket 30 and substantially tangential thereto. The base 24 is secured to the bottom of the casing by bolts (not shown) passed through ears 36 and 31 on base and casing respectively.

The casing 25includes a column 40 which surrounds the shaft 2i and tubes 4| which register at their lower ends with the enlarged outer 130T. tions of the chambers 35. The tubes 41 are connected by the cross-rib 28 which has at its center a sleeve 42 for theshaft 2| andin which the,

bearings 2'! are mounted. The tubes are also connected by base plates 43 which rest upon the;

wall 3| of the base and close the tops of the ports 34. The plates 43 are spaced from the rib 28 and collar 42 to provide openings M to the pocket 30.1

The column 40 of the casing 25 is enlarged'atg vertically separated points to form chambers 45, here shown (see Fig. '7) as annular, into the lower one of which the tubes 4| lead. Each chamber 35 is enlarged at the top and provided with a plurality of openings 4%. Preferably the wall 41 forming the top of each chamber is inclined downwardly and outwardly, and the openings 45 are formed at right angles thereto. As here shown the openings vary in size, the set at the bottom chamber being the smallest and the set at the upper chamber being the largest, but the sizes of the openings may all be thesame or may be otherwise varied, depending upon the material treated or the treatment desired.

The impeller 22 comprises a disk 50 having on its upper and lower faces arcuate vanes, and 52 leading inward from the periphery and a collar 53 by which the impeller is attached to the shaft 2|.

As shown in the drawing the elements of the casing are integral parts thereof. If desired, however, the elements might be separately formed and'fixed in position in any suitable manner, or the casing might be made of two half sections removably connected along a midcentral lowing agitation. The liquid is drawn by the impeller through the openings 32 and M into "the pocket 3d of the base and ejected thereby from the pocket through the ports 3% directly into the container and through the chambers 35 into the tubes 4|. The streams leaving the base through the ports 3*! set up a swirling or spiral movement in the liquid at the bottom of the container, thus breaking up any thickened sediment or masses and ensuring that portions at least of the thickened mass should enter the The cross-rib 28 acts not only to suppocket. port the collar 42 but also acts upon the swirling liquid to break up any inverted vortex that might be set up and to cause the liquid to enter 3 the poclcet 30 through the openings 44.

The liquid forced by the impeller into the chambers escapes therefrom through the tubes 4i into the column of thecasing 25 and the several chambers 55. A portion of the liquid entering each chamber is returned to the main body in the container through the openings '46,

leaving in the form of spouts, indicated on Fig. 1.

' The movement of the liquid thus set up is continued until the contents of the container'are substantially uniform and homogeneous. As the liquid set in circulation is drawn from the bottom of the container, it is of course replaced by liquid from the upper levels It will be noted that the impeller 22 has vanes on its upper and lower surfaces and that, since the mouths of the chambers 35 are both below and above the body of the impeller, liquid is forced into the chambers by both sets of vanes, whereas the mouths of the ports 34 are above the body of the impeller so that liquid is forced into the ports by the upper set of vanes alone. are shown four ports 36 and two diametrically opposite chambers 35. This arrangement has been found to give satisfactory service, but it will be understood that the invention is not limare broken up as they enter the pocket. a breaking up of the particles is further carried out In the drawings the mouth thereof. particular penetrating power and hence it has ited thereto and that other arrangements may be made if desired.

It will be noted that the spaces between the vanes 5| and the plate 43 and between the vanes 52 and the bottom wall of the pocket 30 are narrow and consequently the particles of the liquids This by the centrifugalforce developed by the impeller.

When heavy non-difiusible liquids are being mixed it is most important that the openings 56. be arranged as shown in the drawings. Thereby the greater quantity of the liquid is raised in the column 40 to the upper row of openings before being returned to the container. For example, if the area of the upper row of openings 45- be four times as large as that of the other openings combined and the container have a capacity of fifty gallons the mixer is capable of handling twenty-five gallons per minute of which twenty gallons are returned through the upper row of openings alone, and will form a layer on the top of the mass of liquid. Thus in the course of two minutes all the liquid has pass-ed through the mixer. Should, on the other hand, the device be used primarily as an agitator it is of advantage that all the openingsbe of the same size so that the disturbing action of the liquid discharged from the column be uniformly distributed throughout the container.

Since the liquid in the column 40 rises out of contact with the main body of liquid the friction loss is held at a minimum much lower than that in mixers where'an open stream isprojected upwardly through the mass to be mixed. Thus the operating cost of a mixer embodying this invention is very low, the motor employed being at least one-half the sizeof the motor employed in the form of mixer mentioned above.

Fixed to the column 48 of the casing 25 above in Fig. l the casing 25 is provided with a sleeve 60, here shown as integral with the column 40, which encloses the shaft 2i and leadsinto a pocket Si. Fixed to the shaft 2| is an impeller 62 which is mounted in the mouth of the pocket 5 I. An annular disk 53 which extends across and closes the pocket 5!, rests upon and is fixed to a shoulder 64. Should liquid rise through the space between the shaft 2| and. the sleeve and enter the pocket ii! it will be forced back down the column by the pressure created by the impeller 62 and prevented from escaping past the disk 63. i

Fig. 8 illustrates the top of a similar device wherein other means for preventing the escape of the liquid from the top of the casing 25 are provided. The device here shown is particularly adapted for agitating hot liquids in a closed kettle, the flange it in the casing 25 serving to fixthe device to the kettle (not shown) and to close Liquids so treated possess been found desirable to provide a stufiing'box the upper chamber 45 is a splash plate 56 which having an annular pocket 8| and a passage82 through which the shaft extends, and in which may be inserted a sleeveless .bearing (not shown). Between the sleeve and a disk 83 fixed to the shoulder04 of the casing above the sleeve is formed a chamber 84 into which liquid rising in the casing is conducted by the pocket 8| and passage 82 past the shaft 2|. Leading from the I pocket 8| to the outer surface of the casing is a port 85. A similar port 86 leads from the chamber 84 through the sleeve 80. Thus any liquid that might rise in the casing during the operation of the device is returned to the container through the ports 85 and 80. The mouths of the ports 85 and 86 are usually, as here shown, directed downwardly so that the liquid will flow out under the force of gravity and no splash plate be required. Should, however, conditions arise under which the liquid has considerable head, the ports might be directed upwardly, in which case a splash plate will probably be necessary. I p

The device shown in Fig. 10 differs from those previously described in that it is particularly from the pocket I20 is prevented by a spring adapted for use with liquids containing sand, emery, or other abrasive material. The structure of the device is in general like that of the devices previously described and the corresponding elements will not be described but will be designated in the drawing and referred to herein by the same reference characters.

The particular feature which distinguishes this device from those previously considered is the provision of a stationary tube 90 which encloses the shaft 2|, being supported at the bottom in a rib 9| integral with the casing 25 and at the top in a sleeve 92 having a flange 93 which rests upon the shoulder 64. Packing 94 clamped in a recess 95 of the sleeve 92 by a locking ring. 96

prevents the passage of liquid beyond the sleeve.

Ports 9! similar to ports 46 and 85 and leading from a chamber 98 below the sleeve 92 return to the container any liquid which has risen above the upper chamber 45. The shaft 2| is supported adjacent its lower end by a bearing 99 secured to the rib 9|. 9

Figs. 11, 12, 13 and 14 illustrate another embodiment of this invention in which the device,

instead of being insertable as a unit into a container, is assembled with and forms a part of a container. Supported byIa pedestal I00 is a base IOI to whichis secured awall I02, the base and wall forming a container for the liquid to be agitated. The center portion of the upper surface of the base |0I is in general similar to the base 24 of the embodiments previously described. The base |0I includes a wall |03,ports I04 and chambers I05 which correspond in function and I structure to the wall 3|, ports 34 and chambers 35. An impeller I06 comprising a disk I0'I pro- I vided with vanes I08 at upper andlower SUI! faces is mounted for rotation within a central pocket II0 defined by the wallvI03. A sleeve III, projecting downwardly from the disk I0! through an opening 2 in the bottom of the pocket H0,

the base of the casing and adapted, when the unit I I5 is properly positioned, to register with the chambers I05 of the base. The unit H5 is here shown as made into two half sections adapt ed to be removably assembled by suitable means as, for example, the clamps H8.

The unit H5 is mounted upon the base IOI in any desired manner and is here shown secured by nut and bolt assemblies. II9 passed through overlapped ears I20 of the unit sections and through holes in thebase I 0|. Through the wall of the casing are formed openings I2I arranged in vertically spaced rows. Preferably the size of the openings in the rows is graduated, the smallest being in the lowest row and the largest being in the top row.

. The unit II5 includes a ring I22 which, when unit and base areproperly assembled, rests upon the wall I03 and extends over the vanes I08. Ribs I23 on the unit sections abut (see Fig. 13) over an opening I24 bounded by the ring I22. At the under side of the base IOI is provided an anpacking I3I in an annular recess I32 in the sleeve I2'I which acts. on a rib I33 on the collar I28.

Upon the rotation of the impeller I06 in the pocket I III the liquid in the container is agitated in substantially the same manner as is the liquid in the containers previously described. Liquid drawn through the. opening I24 into the pocket II0is ejected through the ports I04 and into the chambers I05. The streams of liquid from the ports I04 set up a swirling,

whirling motion at thebottom of the container.

The liquid entering the chambers I05 is forced -up through the tubes. II'I into the casing H6 .and escapes from the casing through the opening I2I into the container. The liquid leaves the casing in the form of streams under appreciable pressure and thus acts not only to replace the liquid at the higher levels with liquid from the lowest level, but also to agitate the liquid and thus ensure uniformity.

While the packing I3! normally prevents escape of liquid from the pocket I26, it has been discovered that when the device is operated the rotation of the collar I28 by swirling the liquid varies its pressure to such an extent that some Will escape past the packing. As a further protection, therefore, vanes I35 are formed on the under face of the collar at the periphery (see Fig. 14), which vanes oppose the entry of the liquid. Theribs I23 act, like the cross-rib 28, as a barrier tobreak up the inverted vortex formed by the whirling of the liquid and ensure its entry into the pocket IIO through the opening I24.

It will be noted that the unit II5 is not only demountably assembled with the base IIlI but is also made in two. sections so that it can be easily cleaned. .The casing 25 of the other embodiments may, if desire'd, be similarly constructed.

While certain embodimentsof thisinvention SIB base leading from the pocket and terminating in chambers, said casing including a column extendinginto the container and tubes [connecting said column with said chambers, said column having openings through the wall thereof leading into the interior of the container, and means for rotating said impeller whereby liquid drawn into the pocket from the container is in part discharged through the'ports into the container and is in part driven through said chambers and said tubes into said column and thence through the openings therein into the container.

2. A mixer by which liquid in a container is agitated, comprising a base having a pocket therein and a casing connected to 'said base, an impeller in the pocket of the base, ports connecting the container and the pocket, passages in the base leading from the pocket and terminating in chambers, said casing including a column extending into the container and tubes connecting said column with said chambers, said column having vertically spaced chambers therein, and openings in the walls of said chambers leading into the interior of the container, and

means for rotating said impeller whereby liquid necting the container and the pocket, passages in the base leading from the pocket and terminating in chambers, said casing including a column extending into the container and tubes connecting said column with said chambers, said column having vertically spaced chambers therein and openings in the wall of said chambers leading into the interior of the container, said openings being graduated in size, the set in the bottom chamber being the smallest and the set in the topchamber being thev largest, and means for rotating said impeller whereby liquid drawn into the pocket from the container is in part discharged through the ports into the container and is in part driven through the chambers in the base and the tubes into said column andthe chambers therein and thence returned to the container through the. openings in said lastnamed chambers.

4. A mixer by which liquid in a container is agitated, comprising a base having a] pocket therein and a casing connected to said base, an impeller in the pocket of the base, ports connecting the container and the pocket, passages in the base leading from the pocket and terminating in chambers, said casing including a column extending intothe: container and'tubes connect ing said column with" said chambers, and having openingsthrough the wall of said column into the interior of the container, a shaft extending. through the column. of .the casing and connected to said impeller, and means for'rotating said shaft and the impeller connected thereto whereby liquid drawn into the pocket from the container is in part discharged through said ports into the container and in part driven through the chambers and said tubes into said column and thence return-ed to the container through the openings in said column.

5'. A mixer by which liquid ina container is agitated, comprising a basehaving a pocket therein and a casing connected to-said base, an

by liquid drawn into the pocket from the con tainer is in part discharged through the ports into the container and is in part drawn through said chambers and said tubes into said column and thence through the openings therein into the container. I

6. In a mixer by which liquid in a container is agitated which includes a base having therein a pocket open to the container and a casing connected to the base, an impeller rotatable in said pocket, said impellercomprising a disk and arcuate vanes on the upper and lower faces of the disk, passages in said base leading from the pocket therein and terminating in chambers, tubes connecting said chambers with saidcasing and vmeans for rotating said impeller to draw liquid from the container into the pocket and force such liquid into said chambers'and through said tubes into said casing.

'7. In a mixer by which. liquid in a container is agitated which includes a base having therein a pocket open to the container and ,a casing connected to the base, an impeller rotatable in said pocket, said impeller comprising. a dish and arcuate vanes on the upper and lower faces of the disk, passages in said base leading from the pocket therein and terminating in chambers,

tubes connecting said chambers with said casing and means for rotating said impeller to draw liquid from the container into the pocket and force such liquid into said chambers and through said tubes into said casing, ports leading from said pocket into the container, said ports being in direct communication with the vanesonone face only of therimpeller disk and said passagesthrough the open top, and means for preventing liquid rising in the column above the openings from escaping from the top of the casing, said means including a sleeve which surrounds the shaft and defines an annular passage therewith, a collar fixed on the shaft above said sleeve, and

a disk carried by the collar and resting upon the column, said sleeve, disk and collar defininga pocket closed at the top by said disk and collar which receives any liquid that has risen through the passage defined by the sleeve and shaft.

EDWARD SCHMIDT. 

